Sheet feeding apparatus



y 1939- H. GUMBEL SHEET FEEDING APPARATUS Filed May 11, 1936 Patented May 23, 1939 UNITED STATES PATENT OFFICE SHEET FEEDING APPARATUS Application May 11, 1936, Serial No. 79,148 In Germany May 11, 1935 9 Claims.

The present invention relates to a sheet feeding apparatus, suitable for instance for printing machines in which the sheets are fed to the machine in overlapping relationship.

In the hitherto known sheet feeders of this kind the piled sheets were delivered-by a sheet separating and feeding apparatus including for instance conveyor bands, which fed the sheets with constant running speed within an operating cycle to the working machine. These sheet feeders work sufficiently well if the running speed of the working machine, for instance printing machine, is not great. With higher running speeds of the printing machine or the like on account of the uniform speed of the feeder increasing with the running speed of the printing machine, a uniform laying on the sheets at the front mark of the machine is prevented. Thin papers flatten themselves at the front mark, and thick sheets spring back, so that an accurate sideways registration becomes impossible. The uniform feeding speed of lapped sheets has further the disadvantage that each addition of a sheet from the pile to the conveyor is frequently not brought about with suflicient accuracy. During the addition of the single sheets to the conveyor the rear end of the last sheet added is still over the gripped sheet of the pile being acted upon by the feeding and separating apparatus. Since now the speeds hardly ever agree accurately the forward end of the sheet to be added to the conveyor band is easily displaced, and particularly with rough papers the following on feed of the sheets is made highly inaccurate.'

The invention has for its object to overcome these difliculties, and consists in the use of an accelerating and retarding appliance for the feeder drive. The accelerating and retarding appliance can be so formed that the whole conveyor in the course of a working cycle is first accelerated and then retarded whereby a fine setting of the foremost paper in the case in question is obtained at the front mark of the printing machine. This advantage can moreover also be obtained if the accelerating 'and retarding device only acts on the paper or papers of the conveyor foremost in the case in question.

In sheet feeders of essentially another kind in which the sheets are fed singly one after the other over the feeding table of the machine it is in fact already known to give the feeding alternately an accelerated and retarded speed, through a change-speed gear.

Sheet feeders with overlapping sheet feed have however quite different working processes in the separating of the sheets and their feeding, and also the difficulties of the accurate addition of the single sheets to the conveyor in lapped relation with other sheets thereon do not occur in sheet feeders with sheets fed singly the one 5 after the other.

In sheet feeders with overlapping sheet feeding it has been first made possible by the present invention to use high running speeds of the working machines, e. g. printing machines so that the device may be used for printing machines in a manner free from objection. In this case the running down speed of the feeder is so regulated that the running off conveyor band during the addition of a further sheet of the heap possesses 15 greater or equal running speed than the added sheet.

Thereby, there is ensured a completely frictionless formation of the overlapping series of sheets.

The invention is more particularly described in the accompanying drawing in which:-

Figure 1 shows the overlapping position of the sheets on the feeding apparatus.

Figure 2 the drive of the feeding apparatus with the retarding apparatus in side view.

Figure 3 the retarding apparatus in front view.

In the form of construction shown the sheets are lifted by sucker i from the heap 2, and carjoined to wheel l5, and wheels I4 and 15 both run free on the shaft 10. Also the wheels l2, 13 are united and run on a pin II. The toothed segment piece 18, freely movable on the shaft [0 bears at its upper end the pin II. The shaft 19 which is rotated at the same speed as the shaft III has an eccentric 20 of which the web 2| engages the arm of the segment piece 22. Rotation of the shaft l9 at the same speed as the shaft I0 is effected by a chain 23 which passes around sprockets 24 and 25 fixed on the shafts I0 and I9 respectively.

If now the shafts ill and I9 rotate, the wheels I2, l3 are swung alternately backwards and forwards whereby the chain 16 and the roller 5 receive an accelerated and then a retarded velocity.

The alternating running speed can naturally overlapping of the sheets may be obtained in ways other than that shown, by the use of other sheet separating and feeding devices.

I claim:

1. Sheet feeding apparatus comprising a continuously driven conveyor on which the sheets lie in lapped relation, means for feeding sheets from a supply thereof to the continuously driven conveyor, and means for accelerating and retarding the movement of said continuously driven con-.

veyor.

2. Sheet feeding apparatus comprising a continuously driven endless conveyor on which the sheets lie in lapped relation, means for picking up sheets one after another from a supply thereof and feeding them in succession to the continuously driven endless conveyor, and means for automatically accelerating and retarding the movement of said continuously driven endless conveyor and the lapped sheets carried thereby.

3. Sheet feeding apparatus comprising a continuously driven conveyor on which the sheets lie in lapped relation, means for picking up sheets one after another from a supply thereof and delivering them in succession to the continuously driven conveyor, gear mechanism for continuously driving the conveyor, and means, including oscillatable toothed quadrants operatively associated with the gear mechanism, for automatically accelerating and retarding the movement of said continuously driven conveyor. 1

4. The method of feeding sheets from a supply thereof to a printing or other machine, which comprises separating the sheets one after another from the supply and delivering them continuously in lapped relation to continuously form a stream of lapped sheets, continuously conveying the stream of lapped sheets toward said machine, and alternately accelerating and retarding the movement of said continuously formed andconveyed stream in'synchronism with the delivery of the separated sheets thereto.

5. The method of feeding sheets to a printing or other machine, which comprises separating the sheets one after another from a supply and delivering them continuously in lapped relation to continuously form a stream of lapped sheets,

7 2,159,147 be obtained also with other means. Also the continuously moving the stream of lapped sheets toward said machine, and alternately accelerat-- ing and retarding the movement of the continuously moving stream of lapped sheets so that the speed of movement of the stream is equal to or greater than the speed of movement of a further sheet when it is delivered to saidstream.

6. The method of feeding sheets to a printingor other machine, which comprises separating the sheets one after another from a supply thereof, forwarding the separated sheets successively and arranging them in lapped relation, continuously moving a stream of the lapped sheets toward said machine, and accelerating and retarding the movement of at least the foremost sheet or sheets of said stream.

7. The method of feeding sheets to a printing or other machine, which comprises separating the sheets one after another from a supply thereof, forwarding the separated sheets one after another relative to the supply and arranging said forwarded sheets in lapped relation, continuously moving a stream of the lapped sheets toward said machine, and alternately accelerating and retarding continuous movement of said stream of lapped sheets.

8. The method of feeding sheets to a printing or other machine. which comprises forwarding sheets one after anhther from a supply thereof,

arranging. the forwarded sheets in lapped relation with the trailing edge of each sheet disposed above the leading edge of the following sheet, continuously moving a stream of the lapped sheets toward said machine, and alternately accelerating and retarding the continuous movement of said stream of lapped sheets.

9. The method of feeding sheets to a printing or other machine, which comprises separating the sheets one after another from the rear of a supply thereof, forwarding each separated sheet from the rear of the supply under a preceding forwarded sheet-to'provide' a stream of lapped sheets, continuously moving the stream of lapped sheets toward said machine, and alternately accelratlng andretarding thecontinuous-movement of said stream' of lapped sheets.

GUMBEL. 

